It is a well-known fact that adapters made of a soft material, namely plastics, resins, etc., are frequently used to screw metallic parts to each other and vice versa. This is the case of adapters used for watering equipment, adapters used in fumigators or sprays for farming purposes, and so on.
These unions, when effected using identical or similar materials, for instance plastic nut and plastic bolt or metal nut and metal bolt, pose no problems and yet when materials of different hardness are used together, for instance when the nut is metallic (hard) and the screw plastic (soft), and particularly when the screw threads are rather thin, special care is required for the nut's screw thread to register with the bolt's screw thread, for the metallic element's screw thread could act as a diestock on the plastic element, along a slightly oblique axis as regards the original screw thread, causing the nut to be seized without same or the bolt being able to move forward, and the nut itself thus being ruined, for the original screw thread will have been partially or completely eliminated. This problem obviously arises both when the nut is hard and the bolt soft, and, alternatively, when the nut is soft and the bolt hard.